# Formula Defaults

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This page is part of the Workshop, one of three main sections of Tower Grove Feed. The other two are Setup and the Workbench. For an overview of the Workshop go to Workshop overview.

## Formula Defaults Fields

Formula Defaults affect the Solve's appearance or calculations.

### Maximum Iterations

The Solve algorithm will abort with error message "Maximum iteration limit exceeded" if it takes more iterations than Maximum Iterations.

The default value for Maximum Iterations is 200 which will normally do for for a matrix size of about 40 rows and 40 columns. A value of 400 will usually suffice for a matrix size of 50.

If the algorithm keeps exceeding Maximum Iterations, increase it or solve as Opt Den (Optimum Density) with W - WeightLimits and a Rng% (Optimum Density Range Percent) of 0.

### Optimum Density

Optimum Density specifies whether or not the solution calculations should find the optimum yield for the diet without having to produce the exact batch weight specified for the formula. If there is a least cost diet that meets the formula's requirements but with a yield lower or higher than the batch weight, then that diet will be the solution regardless of its final yield.

Optimum Density allows the solve algorithm to increase (or decrease) yield in order to find the optimum nutrient density, resulting in a lower cost than solving with the formula's batch weight. Nutrient density is an important tool in feeding animals under conditions of heat or stress.

Two fields control the use of Optimum Density: the optimum density code and the range percentage.

The Optimum Density codes are:

1. "Y - Yes" to find the optimum yield
2. "N - No" to use the fixed batch weight (the default)
3. "W - WeightLimits" to find the optimum yield within specific limits

If you specify "W-weight limits" you should also specify a range percentage. This is the range within which the solution may vary from the specified batch weight. For example if the batch weight is 1000 and the range percentage is 10%, then the solution yield may be anywhere from 900 to 1100.

Helpful hint: The two optimum density codes use a different model for solving than the fixed batch weight model. A code of "W-weight limits" and a range percentage of zero specifies the same batch weight as "N - No", but uses the optimum density model in the solve. This can be useful for cases where the solve has difficulties with "N - No".

### Optimum Density Range Percent

Optimum Density Range Percent specifies the upper and lower limits for the optimum density calculations when Optimum Density is set to "W - WeightLimits".

For example, if the batch weight is 1000, an Optimum Density Range Percent of 5.00 will constrain the solve to find the optimum yield within a range of 950 to 1050.

### Default Batch Weight

The Default Batch Weight value is used automatically when a formula is first created, but it may always be overridden for a specific formula. A typical value is 1000.

### Weight Unit of Measure

The unit of measure indicates the type of measurement to record weights. The choice is almost always between 'pounds - lb' and 'kilograms - kg'. The unit of measure applies to the batch weight, the weights of ingredients in the formula solution, and to ingredient cost units. You could also select 'tons' or 'metric tons' but these are not typically used. Pound (lb) usually refers to an avoirdupois pound.

The unit of measure is specified on the Formula defaults page in the Workshop.

Currently the unit of measure designation is for information only. If you change the unit of measure, Tower Grove Feed does not recalculate ingredient costs or reset batch weight or costs automatically. If, for example, you change from kilograms to pounds, the most common thing to do is to set change the Formula defaults batch weight to 2000 and also set the Control level defaults cost units to 2000.

### Dry Matter Only

This field sets the default value for all formulas at or below the current control level.

The Dry Matter field is a check box that determines whether the solution nutrients and the Batch Weight are to be considered as 100% dry matter. Solution ingredients will be shown “as is.”

If checked, solution nutrients and Batch Weight are shown as 100% dry matter.

If unchecked (default) solution Nutrients and Batch Weight are shown “as is.”

## Workshop overview

The Workshop is one of three main sections of Tower Grove Feed. The other two are the Workbench and the Setup.
The Workshop provides access to the information you normally need in setting up formulas. By default, when you log in, you arrive at the formula list, which you can return to from other Workshop pages by clicking the Formulas tab. The formula list provides access to the Workbench where you can work on a particular formula.

The two other pages in the Workshop are the Ingredients and the Formula defaults pages. (Note: There are two additional tabs on the Workshop page, but these tabs take you to pages outside of the Workshop.)

The list of tabs in the Workshop are as follows:

## Workshop tabs

### Formulas

The list of formulas (diets) that you have access to at the current control level. To get to the Workbench for a particular formula, click on the name of that formula.

### Ingredients

An editable list of ingredients. All formula ingredients must exist in this master ingredient list.

### Defaults

The Formula Defaults page includes fields that control the solution calculation or the appearance of formulas.

### Setup

The Setup area provides access to nutrients, species, control levels, ingredient types, user profile information, control level defaults, and the copy/move facility.

### Workbench

This tab takes you to the last formula you were working on in the Workbench.